Enhanced gustatory neural responses to sugars in the diabetic db/db mouse

1995 ◽  
Vol 269 (4) ◽  
pp. R930-R937 ◽  
Author(s):  
Y. Ninomiya ◽  
N. Sako ◽  
Y. Imai
Keyword(s):  
Genetic Model ◽  
Major Gene ◽  
Common Factor ◽  
Preference Test ◽  
Taste Preference ◽  
Sweet Taste ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Neural Responses ◽  
Behavioral Experiments

Sweet taste sensitivity in a genetic model of diabetes, the db/db mouse, in which a single major gene defect leads to the expression of diabetes and obesity, was studied by examining chorda tympani nerve responses to various taste stimuli, including sugars. The chorda tympani responses to four sugars, sucrose, fructose, glucose, and maltose, in adult db/db mice showed greater relative magnitudes and lower thresholds than those in adult lean mice, but responses to other basic taste stimuli, such as NaCl, HCl, and quinine HCl, were not different in the two groups. Behavioral experiments using a two-bottle preference test demonstrated that taste preference scores for the four sugars at suprathreshold concentrations, except 1.0 M, were higher in db/db than in control mice. Infant mice of 7-9 days of age possessing the genotype db/db also exhibited greater neural responses and lower thresholds for sugars than infant control mice, whereas streptozotocin-induced adult diabetic mice possessing the genotype +/+ did not exhibit larger sugar responses. These findings suggest that the enhanced sugar sensitivities observed in db/db mice are probably determined by a single major gene, db. The db gene may act on a common factor(s) involved in the stimulus-secretion coupling in the pancreatic B cell and the taste cell of db/db mice.

Behavioral and Neural Responses to Vitamin C Solution in Vitamin C-deficient Osteogenic Disorder Shionogi/Shi Jcl-od/od Rats

2019 ◽  
Vol 44 (6) ◽  
pp. 389-397
Author(s):  
Toshiaki Yasuo ◽  
Takeshi Suwabe ◽  
Noritaka Sako
Keyword(s):  
Vitamin C ◽  
Behavioral Study ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Neural Responses ◽  
Wild Type ◽  
Behavioral Experiments ◽  
Aversive Taste ◽  
Salty Taste ◽  
Preference Tests

Abstract To investigate the appetite for vitamin C (VC), we conducted behavioral and neural experiments using osteogenic disorder Shionogi/Shi Jcl-od/od (od/od) rats, which lack the ability to synthesize VC, and their wild-type controls osteogenic disorder Shionogi/Shi Jcl- +/+ (+/+) rats. In the behavioral study, rats were deprived of VC for 25 days and then received two-bottle preference tests with a choice between water and 10 mM VC. The preference for 10 mM VC solution of od/od rats was significantly greater than that of +/+ rats. In the neural study, the relative magnitudes of the whole chorda tympani nerve (CTN) responses to 100–1000 mM VC, 3–10 mM HCl, 100–1000 mM NaCl, and 20 mM quinine▪HCl in the VC-deficient rats were significantly smaller than those in the nondeficient ones. Further, we conducted additional behavioral experiments to investigate the appetite for sour and salty taste solutions of VC-deficient od/od rats. Preference scores for 3 mM citric acid increased in od/od rats after VC removal, compared with before, whereas preference scores for 100 and 150 mM NaCl were decreased in VC-deficient od/od rats. The preference for 300 mM NaCl was not changed. Hence, our results suggest that the reduction of the aversive taste of VC during VC deficiency may have involved the reduction of CTN responses to acids. Overall, our results indicate that VC-deficient rats ingest sufficient VC to relieve their deficiency and that VC deficiency causes changes in peripheral sensitivity to acids, but nongustatory factors may also affect VC intake and choice.

Sweet Taste Responses of Mouse Chorda Tympani Neurons: Existence of Gurmarin-Sensitive and -Insensitive Receptor Components

1999 ◽  
Vol 81 (6) ◽  
pp. 3087-3091 ◽  
Author(s):  
Yuzo Ninomiya ◽  
Toshiaki Imoto ◽  
Tadataka Sugimura
Keyword(s):  
Sweet Taste ◽  
The Other ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Single Fibers ◽  
Taste Cells ◽  
C57bl Mice ◽  
Mouse Taste

Sweet taste responses of mouse chorda tympani neurons: existence of gurmarin-sensitive and -insensitive receptor components. Inhibitory effects of gurmarin (gur) on responses to sucrose and other sweeteners of single fibers of the chorda tympani nerve in C57BL mice were examined. Of 30 single fibers that strongly responded to 0.5 M sucrose but were not or to lesser extent responsive to 0.1 M NaCl, 0.01 M HCl, and 0.02 M quinine HCl (sucrose-best fibers), 16 fibers showed large suppression of responses to sucrose and other sweeteners by lingual treatment with 4.8 μM (∼20 μg/ml) gur (suppressed to 4–52% of control: gur-sensitive fibers), whereas the remaining 14 fibers showed no such gur inhibition (77–106% of control: gur-insensitive fibers). In gur-sensitive fibers, responses to sucrose inhibited by gur recovered to ∼70% of control responses after rinsing the tongue with 15 mM β-cyclodextrin and were almost abolished by further treatment with 2% pronase. In gur-insensitive fibers, sucrose responses were not inhibited by gur, but were largely suppressed by pronase. These results suggest existence of two different receptor components for sweeteners with different susceptibilities to gur in mouse taste cells, one gur sensitive and the other gur insensitive. Taste cells possessing each component may be specifically innervated by a particular type of chorda tympani neurons.

Recovery of two independent sweet taste systems during regeneration of the mouse chorda tympani nerve after nerve crush

2007 ◽  
Vol 26 (6) ◽  
pp. 1521-1529 ◽  
Author(s):  
Keiko Yasumatsu ◽  
Yoko Kusuhara ◽  
Noriatsu Shigemura ◽  
Yuzo Ninomiya
Keyword(s):  
Sweet Taste ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Nerve Crush

Enhancement of sweet taste responses by the addition of salt compounds in the mouse chorda tympani nerve

2009 ◽  
Vol 65 ◽  
pp. S175
Author(s):  
Tadahiro Ohkuri ◽  
Keiko Yasumatsu ◽  
Margolskee Robert F ◽  
Yuzo Ninomiya
Keyword(s):  
Sweet Taste ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve

scholarly journals T1R3 taste receptor is critical for sucrose but not Polycose taste

2009 ◽  
Vol 296 (4) ◽  
pp. R866-R876 ◽  
Author(s):  
Steven Zukerman ◽  
John I. Glendinning ◽  
Robert F. Margolskee ◽  
Anthony Sclafani
Keyword(s):  
Critical Role ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Sucrose Preference ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Sweet Taste Receptor ◽  
Sucrose Solutions ◽  
Nerve Recordings

In addition to their well-known preference for sugars, mice and rats avidly consume starch-derived glucose polymers (e.g., Polycose). T1R3 is a component of the mammalian sweet taste receptor that mediates the preference for sugars and artificial sweeteners in mammals. We examined the role of the T1R3 receptor in the ingestive response of mice to Polycose and sucrose. In 60-s two-bottle tests, knockout (KO) mice preferred Polycose solutions (4–32%) to water, although their overall preference was lower than WT mice (82% vs. 94%). KO mice also preferred Polycose (0.5–32%) in 24-h two-bottle tests, although less so than WT mice at dilute concentrations (0.5–4%). In contrast, KO mice failed to prefer sucrose to water in 60-s tests. In 24-h tests, KO mice were indifferent to 0.5–8% sucrose, but preferred 16–32% sucrose; this latter result may reflect the post-oral effects of sucrose. Overall sucrose preference and intake were substantially less in KO mice than WT mice. However, when retested with 0.5–32% sucrose solutions, the KO mice preferred all sucrose concentrations, although they drank less sugar than WT mice. The experience-induced sucrose preference is attributed to a post-oral conditioned preference for the T1R3-independent orosensory features of the sugar solutions (odor, texture, T1R2-mediated taste). Chorda tympani nerve recordings revealed virtually no response to sucrose in KO mice, but a near-normal response to Polycose. These results indicate that the T1R3 receptor plays a critical role in the taste-mediated response to sucrose but not Polycose.

Gurmarin inhibition of sweet taste responses in mice

1995 ◽  
Vol 268 (4) ◽  
pp. R1019-R1025 ◽  
Author(s):  
Y. Ninomiya ◽  
T. Imoto
Keyword(s):  
Sweet Taste ◽  
Suppressive Effect ◽  
Taste Receptors ◽  
Gymnema Sylvestre ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Sweet Taste Receptors ◽  
Before And After ◽  
C57bl Mice

The inhibitory effects of gurmarin (a peptide isolated from the leaves of Gymnema sylvestre) on sweet taste responses were studied by examining the chorda tympani nerve responses to various taste substances before and after lingual treatment with gurmarin in C57BL and BALB mice. Treatment with gurmarin at 3 micrograms/ml or more selectively suppressed responses to sucrose without affecting responses to NaCl, HCl, and quinine in C57BL mice, whereas gurmarin at 100 micrograms/ml did not significantly suppress sucrose responses in BALB mice. Responses to various sweet substances in C57BL mice decreased to approximately 45-75% of control after gurmarin, and the suppressive effect of gurmarin was reversible. The profile of the residual responses of C57BL mice to various sweeteners after gurmarin was almost identical to that of BALB mice, which was hardly affected by gurmarin. These results strongly suggest that there are at least two types of sweet taste receptors in mice, gurmarin-sensitive and -insensitive. Probably, C57BL and BALB mice share an identical gurmarin-insensitive receptor, and C57BL mice also have a gurmarin-sensitive receptor.

Modulations of sweet taste responses by salts, acids and bitter compounds in the mouse chorda tympani nerve

2007 ◽  
Vol 58 ◽  
pp. S217
Author(s):  
Keiko Yasumatsu ◽  
Ryusuke Yoshida ◽  
Robert F. Margolskee ◽  
Yuzo Ninomiya
Keyword(s):  
Sweet Taste ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve

scholarly journals Taste does not determine daily intake of dilute sugar solutions in mice

2010 ◽  
Vol 299 (5) ◽  
pp. R1333-R1341 ◽  
Author(s):  
J. I. Glendinning ◽  
F. Beltran ◽  
L. Benton ◽  
S. Cheng ◽  
J. Gieseke ◽  
...  
Keyword(s):  
Daily Intake ◽  
Sweet Taste ◽  
Relative Magnitude ◽  
The Body ◽  
Taste Intensity ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
The Central Nervous System ◽  
Daily Intakes ◽  
Stimulus Identification

When a rodent licks a sweet-tasting solution, taste circuits in the central nervous system that facilitate stimulus identification, motivate intake, and prepare the body for digestion are activated. Here, we asked whether taste also determines daily intake of sugar solutions in C57BL/6 mice. We tested several dilute concentrations of glucose (167, 250, and 333 mM) and fructose (167, 250, and 333 mM). In addition, we tested saccharin (38 mM), alone and in binary mixture with each of the sugar concentrations, to manipulate sweet taste intensity while holding caloric value constant. In experiment 1, we measured taste responsiveness to the sweetener solutions in two ways: chorda tympani nerve responses and short-term lick tests. For both measures, the mice exhibited the following relative magnitude of responsiveness: binary mixtures > saccharin > individual sugars. In experiment 2, we asked whether the taste measures reliably predicted daily intake of the sweetener solutions. No such relationship was observed. The glucose solutions elicited weak taste responses but high daily intakes, whereas the fructose solutions elicited weak taste responses and low daily intakes. On the other hand, the saccharin + glucose solutions elicited strong taste responses and high daily intakes, while the saccharin + fructose solutions elicited strong taste responses but low daily intakes. Overall, we found that 1) daily intake of the sweetener solutions varied independently of the magnitude of the taste responses and 2) the solutions containing glucose stimulated substantially higher daily intakes than did the solutions containing isomolar concentrations of fructose. Given prior work demonstrating greater postoral stimulation of feeding by glucose than fructose, we propose that the magnitude of postoral nutritive stimulation plays a more important role than does taste in determining daily intake of dilute sugar solutions.

Low environmental temperature modulates gustatory nerve activity and behavioral responses to NaCl in rats

1999 ◽  
Vol 277 (2) ◽  
pp. R368-R373 ◽  
Author(s):  
Yasutake Shimizu ◽  
Keiichi Tonosaki
Keyword(s):  
Ambient Temperature ◽  
Cold Exposure ◽  
Cell Function ◽  
Preference Test ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Sodium Channel Blocker ◽  
Behavioral Studies ◽  
Electrophysiological Recordings ◽  
Gustatory Nerve

We studied the effects of cold ambient temperature on chorda tympani nerve responses to taste stimuli such as sucrose, NaCl, quinine HCl (QHCl), and HCl in rats. The electrophysiological recordings of the whole chorda tympani nerves from control (22°C) and cold-exposed (4°C) rats revealed that the responses to sucrose, HCl, and QHCl were unaffected by cold exposure. In contrast, the nerve responses to NaCl were enhanced time dependently, reaching a maximum 7–14 days after cold exposure. Responses to sodium acetate were likewise elevated as they were to NaCl, whereas those to KCl were unchanged after cold exposure. In addition, the residual NaCl responses after lingual application of the sodium-channel blocker amiloride in cold-exposed rats were similar to those in control animals. It is thus most likely that cold exposure potentiates the chorda tympani nerve responses to Na+, but not to Cl−. Behavioral studies with the two-bottle preference test showed that the cold-exposed rats refused to drink NaCl solutions at 0.05 and 0.1 M, the concentrations being preferred by control animals. These results suggest that the ambient temperature influences taste cell function, and that the enhanced NaCl response of the chorda tympani nerve is related to the avoidance of NaCl intake under cold environment.

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